Multiple switchboard for telephone-exchanges



N0 Model'.)

M. G. KELLOGG. MULTIPLE SWITGHBOARD FOB TELEPHONE EXCHANGES. N0.542,262.

Patented July 9, 1895.

UNITED; STATES PATENT OFFICE.

- MILO e; KELLO'GG, or emcee-0', ILLINOIS.

MULTIPLE SWITCHBOARD FOR TELEPHONE-EXCHANGES.

' SPECIFICATION forming part Letters Patent No. 542,262, dated July 9,1895.

' Application filed December 21, 1889. Serial Ho. 884,519. (No model.) i

To all whom itmay concern:

Be it 'knownthat I, MILO G. KELLOGG, of Chicago, Illinois, temporarilyresiding at Stuttgart, in the Empire of Germany, have invented certainnew and useful Improvements in Multiple Switchboards forTelephone-Exchanges, of which the following is a full, clear, concise,and exact description, reference being had to the accompanying drawings,formin g a part of this specification.

My invention relates more especially to the multiple-switchboard systemdescribed in my Patent No. 308,315, dated November 18, 1884-, andsimilar systems.

' It consists of a "compound spring-jack switch, hereinafterdescribedand claimed, designed to be used in the switchboards of the centraloffice of a telephone-exchange.- I The organization whereby the twopairs of contacts areoperated on the insertion of aswitohplug is,however, novel aside from any pat ticular system to which the switch maybe adapted, and though I show and describe the switch in connection witha particular system I do not limit myself to the special connection ofthe contacts in my switch, whereby the desired operations in theparticular system shown herein are accomplished.

In the accompanyingdrawings, representingmy invention, Figure 1represents a side view of sections of two multiple switchboards, towhich the same lines are connected, and a diagram of the local circuits,connections, and

A A are broken sectional views of the frameworks of the switchboardsadapted to receive the spring-jack switches.

.lis the metalfraine of the switch, having a hole through its front andadapted to receive a switch-plug and operate the switch parts.

d is a metal contact screw or point passing parts are indicated bthrough the frame Z andinsulated from it'by the insulation 0, which alsopasses through Z.

c is a contact spring or piece, which is also insulated from the metalframe I, and is in contact withthe point b of screw d when the wedge orplug is not inserted 'into the switch. When the wedge or plug'isinserted into the switch the contact between point I) and spring e isbroken, as shown in board A.

b and e are a-pair'of contacts, and as I use them in opening and closinga subscribersv telephone-line I call them the main line contacts of myswitch.

7a is a connecting-piece in electric connection with screw d.

his a contact-point, in this insiance ,connected with the metal frame ofthe switch, as shown. I

f is a' contact spring or piece, which is insulated from the frame I,andalso from the contact-spring e, and is in contact with the point hwhen the wedge or plugis inserted into the switch. When a wedge or plugis not in the switch, the contact between the point h and springf isopen, as shown.

h and f are a pair of contacts, and as I use them-in opening andclosinga local circuit in my multiple switch-board system,I call them lis a connecting-piece in electric connection with the framework'l.

m',m", and m areinsuIating-pieces,which insulate springs e and f fromeach other and from the frame L. An extension of Z passes through thesepieces and has a screw-thread cut on it. n is a nut which fits thisthread and holds the parts in place, as shown.

I have shown a. plug inserted in to the righthand switch shown on boardA.

Fig. 3 shows a wedge or plug adapted for use with my spring-jack switch.0 is the handle of the plug, and ismade of some insulating material, ashard rubber. C is a solid metal cylinder with round end, as shown.

C" is a rubber cylinder surrounding the metsl cylinder, except at therounded end, as shown. D'is a flexible insulated conductingcord inelectric connection with the metal cylinder C'through the metalstrip E.

It will be seen that when there is no plug in the switch there iselectric contact between the points b and" e, and that the points h andfare open to each other, and also that the switch-frame is insulatedfrom all these points except the contact h thereon.

It will also be seen that when a plug is in the switch the electriccbntact between 12 and eis broken, and that the contact between 72andfis made, and that the metal cylinder of the plugis in contact withthe spring e and that the metal switch-frame is insulated from the parts6 e and the plug-contact, 'and is in connection with f through thecontact h.

The point I) and spring e,,with the plug and cord, constitute themain-line switch in my system. The point It and spring f, whereby thelocal circuit is automatically closed by the insertion of the plug forswitching the main line, constitute a local circuit-closer. The metalswitch-frame Z, being always insulated from the other working parts ofthe switch, except the contactf, when a plug is inserted, and from theplug, except through the arrangement of circuits hereinafter shown,constitutes a test-plate in my system of multiple switchboards, and Icall its front end, which extends to the front of the board, atest-contact, and this test -contact is in electrical connection withthe point h.

T are the test-plugs, and t are the test-receiving instruments, one plugand one instrument for each switch-board.

B .B are test-batteries.

The connections of the main lines through the main-line contact-pointson the several boards are as shown.

I have not represented the operators cord system and apparatus indetail,as well-known forms'bf apparatus may be used for switching .theJines.

The localtest'circuits and connections are as follows: All thecontact-pieces ff of the switches on the several boards are connectedtogether and are connected to one side of each of the testreceivinginstruments. All the metal frames of the switches of aline (to which areelectrically connected the contactpicces h of their respective switches)are connected together. To the other side of each test-receivinginstrument from that mentioned above is connected its test plug'ordevice by a cord of such length that the plug can readily be broughtinto contact for testing with any metal piece lat its board. In thecircuit of each test-receiving instrument between its test-plug and thepoint where it is connected with the group of contact'piece'sf f of theexchange is an electric battery.

When a line is tested at any bo'ard by the test-plug being applied tothe metal frame 1 of the line tested and the line is switched at anyboard the test-receiving instrument will sound or respond, thetest-circuit being complete through the frame of the switch tested tothe frame of the switch that is switched or plugged and its pair oflocal contacts hf to one side of the test-battery B. \Vhen on the testbeing made the line is not switched there is no complete circuit, noneof the contacts h f being closed, and the instrument will not sound orrespond. The operator can there fore determine on testing whether or notany line is switched for use.

By the construction and arrangement of the parts as shown and describedabove the switch and test apparatus is less complicated and ismorecondensed than is found in other apparatus constructed for use inmultipleswitchboard systems which have independent local test-circuitsfor the lines.

I claim as my invention 1. A spring jack switch, adapted to receive aswitch-plug, consisting of a metal frame through the frontof which isthe switch hole, a contact spring or piece placed with its lengthparallel to the axis of the hole, a secend-contact spriuginsnlated fromand parallel with the first contact-spring and operated by it to bepressed into contact with 'a contact point or piece while a plug is inthe switch hole, substantially as set forth.

2. A spring jack switch, adapted to receive a switch plug, consistizg ofa metal frame through the front of which is the switch .hole, acontacbspring or piece insulated from the metal frame and placed withits length parallel to the axis of the hole, and a second contact springor piece insulated from the first contact-spring and normally insulatedfrom the metal frame, placed parallel to said first spring and operatedby it to be pressed into connection with said metal frame while a plugis in the switch hole, substantially as set forth.

3. A spring jack switch,adapted to receive a switch plug, consisting ofa metal frame through the front of whichis the switch hole, a contact-poiut insulated from the metal frame, a contact-spring or piece.insulated from the metal frame, placed with its length parallel to theaxis of the switch hole and nor mally in contact with saidcoutact-point,and a second contact-piece or spring insulated from thefirst contact spring normally-insulated from the metal frame, and placedparallel to the first spring, said first spring being operated by theplug, on its insertion, to be pressed awayfrom its normal connectionwith its contact-point and to press the other contact -piece intoconnection with the metal frame, substantially as set forth.

4. In a spring jack switch, acontact-spring or-piece placed with itslength parallel to the axisoftheswitch hole, a second contact-spring orpiece insulated frourand parallel with the first contact spring and acontact-point nor mally insulated from both contact-springs said switchbeing adapted to receive a switch plug, which on its insertion, movesthe first point, substantially as set forth.

In a spring jack switch, a contact-spring or piece placed with itslength parallel to theaxis of the switch hole and normally incontact-with a contact-point, a second contactspring or pieceplacedparallel to and insulated from. the first spring, and anothercontact-point normallyinsulated from the rest, said switch beingadaptedto receive a switch plug, which on its insertion, moves the firstcontact-spring away from its contact-point -with which it is normally incontact, and

presses the second contact spring into connection with saidothercontact-point, substantially as set forth. I

6. In a spring jack switch, a metal frame extending to the front of the'switch board and through the front of which is a switchhole,acontact-spring or piece placed with its length parallel to theswitch hole, a second contact-spring or piece insulated from andparallel with the first contact-spring and normally insulated from themetal frame, said switch being adapted to receiveaswitch plug which, onits insertion, moves the contactspring, and said contact. spring whenthus moved presses the contact-piece into connection with the metalframe, substantially as set forth.

7. Ina spring jack switch, a metal frame extending to the front of theswitch board and through the front of which. is a switch hole, a contactspring or piece placed parallel to the switch hole and insulated fromthe metal frame a con tact point with which said.

hole, a second contact spring insulatedv from and parallel with thefirst contact spring, 3;

- contact-point normally insulated from the second contact-piece andelectrically connectcd with a' metal test contact piece on the front ofthe switch board, said switch being adapted to receive a switch-plugwhich on its insertion, moves the first contact-spring and presses thesecond contact spring into con-- nection with said as set forth. .9. Ina'spring jack switch,a contactspring placed with its length-parallel tothe switch hole, a contact point with which the spring is normally incontact a second contact spring or pi ce'insulated from the firstcontactspring contact-point, substantially and placed parallel to it, and acontact point ndrmally insulated from the second contact.

spring, and a. test-piece placed on the front of the switch board withwhich the last named .contact point is el'ectrically'counected, saidswitch beingadapted to receive a switch-plug which on its insertion,moves'the firstspringaway from its normal connection'withitscontact-point and presses the second con tact-' piece into connectionwith itscontactpoint,

substantially as set forth.

10. The combination of the frame-work hav,

mounted on said fi-ame-wo'rkjwith one end in the hole andhaving insaidend a switch hole" for the reception of aswitch plug, two insulatedcontact-pieces or springs carried by said frame,an insulated contactpoint also carried by the metal frame and with which one of said springsis normally in contact, and another contact point also carried by saidmetal frame with which 'the other spring is normally out of contact, thearrangement being such that when a .switch plug is inserted one contactspring moves out of contact with the point with which it is normally incontact, and the other spring moves into contact with the point withwhich it is normally out of contact. X

11. The combination of the frame-work having a. hole therein forthe-insertion of a switch plug, two contact-pieces or springs insulatedfrom each other, arranged in the rear of the frame-work parallel, orsubstantially so, with the axis of the switch hole, a contact point withwhich one of the springs is normally in contact and another contactpoint with which the other spring is normally out of contact, thearrangement being such that when a switch plug is inserted one spring ispressed out of contact with its contact-point and the otherv insertedinto the switch hole, one spring is pressed out of contact with thepoint against which it normally bears, and the other spring is pressedinto contact with the point with which it is normally out of contact.

13. The combination, of theframe-work having a hole therein for theinsertion of a switch plug, two contact pieces or springs, insulatedfrom each other, arranged in rear of the framework, parallel,orsubstantially so, with the axis of the switch hole, an insulatedcontact point upon which one ofthe springs normally bears, anothercontact-point with which the other spring is normally out of contact,and

IIO

a metal test piece or contact at the front of the switch board withwhich piece the last named contact is in electrical connection.

14. Inaspringjack switch the combination, with the frame work oftheswitch board, two

insulated contact-pieces or springs arranged in 1.;nr of the frame-workparallel with each other, or substantially so, and at right angles tothe plane of the face of the frame-work, a contact point against whichone of the springs normally bears, and another contact point with whichthe other spring is normally out of contact, of a. switch plug, adaptedto be inserted into the switch, the arrangement being such that when theplug is inserted one spring is pressed out of contact with the contactpoint against which it normally bears, and the other spring is pressedinto contact with the contact point with which it is norinnlly out ofcontact.

In witness whereof I hereunto subscribe my name this 29th day ofNovember, 1889.

MILO G. KELLOGG. \Vitnesscs:

EMIL AB'ENHEIM, ll'lARGARETHA PRIEIIL.

